make vulkansdk an explicit package (#1574)

packages/v/vulkansdk/xmake.lua

@@ -0,0 +1,38 @@
+package("vulkansdk")
+
+    set_homepage("https://www.lunarg.com/vulkan-sdk/")
+    set_description("LunarG Vulkan® SDK")
+
+    add_configs("shared", {description = "Build shared library.", default = true, type = "boolean", readonly = true})
+    add_configs("utils",  {description = "enabled vulkan utilities.", default = {}, type = "table"})
+
+    on_load(function (package)
+        import("detect.sdks.find_vulkansdk")
+        local vulkansdk = find_vulkansdk()
+        if vulkansdk then
+            package:addenv("PATH", vulkansdk.bindir)
+        end
+    end)
+
+    on_fetch(function (package, opt)
+        if opt.system then
+            import("detect.sdks.find_vulkansdk")
+            import("lib.detect.find_library")
+
+            local vulkansdk = find_vulkansdk()
+            if vulkansdk then
+                local result = {includedirs = vulkansdk.includedirs, linkdirs = vulkansdk.linkdirs, links = {}}
+                local utils = package:config("utils")
+                table.insert(utils, package:is_plat("windows") and "vulkan-1" or "vulkan")
+        
+                for _, util in ipairs(utils) do
+                    if not find_library(util, vulkansdk.linkdirs) then
+                        wprint(format("The library %s for %s is not found!", util, package:arch()))
+                        return
+                    end
+                    table.insert(result.links, util)
+                end
+                return result
+            end
+        end
+    end)